A gas chromatograph/mass spectrometer (typically abbreviated as “GC/MS”) analyzes a sample of material to determine the constituent compounds thereof. For example, a GC/MS can be used to determine the compounds that are in a sample of food. In one application, a GC/MS analyzes food products to detect the presence of contaminants, such as a pesticide, a chemical warfare agent (CWA), or other contaminants present in the sample. The sample is also referred to as a “matrix” or “sample matrix.” Typically, a GC/MS analyzes a sample using both time-based parameters (for example, identifying a target compound based on a time window, referred to as “retention time”) and on mass-to-charge ratio, referred to as “m/z,” that identifies ions present in the target compound. For a sample having multiple components, the GC/MS outputs a signal that is represented by a pulse train having multiple peaks. The position of each peak relates to the identity of the components in the mixture while the area of the peak relates to the quantity (also referred to as abundance) of that component in the mixture.
When a target compound is detected in the sample matrix, the identity of the target compound must be verified. Verification of the target compound is typically automated, but manual review of the analysis results is required to validate the results.
Typically, a number of different software programs may be used to process the results of the analysis performed by the GC/MS. A first program can be used to analyze the results of the GC portion of the GC/MS and to analyze the results of the MS portion of the GC/MS. A second program may be used to confirm the results by comparison with a known database.
Typically, an analyst who must be proficient in the use of the above-mentioned software may require on the order of 20–30 minutes to perform peak averaging and background subtraction to confirm a target compound found by a retention time window analysis and four (4) ion identification. Unfortunately, this confirmation process is time consuming and burdensome, due to matrix interferences. As known by those skilled in the art, matrix interferences are those compounds present in a sample in which one is not interested. They have similar retention times and/or similar ion fingerprints that obscure correct identification of the compounds in which one is interested, which are referred to as the target compounds.
Therefore, it would be desirable to automate the identification and verification of a target compound detected in a sample.